Add IIO example to the kernelnewbies wiki
Gaston Gonzalez
gascoar at gmail.com
Thu Feb 21 13:56:37 EST 2019
On Wed, May 09, 2018 at 10:21:08AM +0300, Daniel Baluta wrote:
> Sure, you can do that. Nice to see that you are using Diolan DLN-2 adapter.
>
> thanks,
> Daniel.
>
> On Mon, Apr 2, 2018 at 8:06 PM, Gaston Gonzalez <gascoar at gmail.com> wrote:
> > Hi,
> >
> > I'm testing an AD7746 eval board using a Diolan DLN-2 adapter. I wrote
> > some basic notes about the installation an instanciation process for my
> > own use. But then I thought it could be useful for someone else. So
> > maybe I could put this in the kernel newbies page under the IIO section?
> >
> > If you think is worth it, I would be glad to add it to the wiki page.
> >
> > Best regards,
> >
> > Gaston
> >
> > Notes:
> >
> > The setup
> > =========
> >
> > AD7746-EVAL BOARD --> Diolan DLN-2 Adapter --> Thinkpad T430
> >
> > The connection between the AD7746 eval board and adapter is as detailed
> > in [2] I2C Interface Configuration Options, External connection (pag 4).
> >
> > The connection between Diolan DLN-2 and the T430 is USB straighforward.
> >
> > Drivers
> > =======
> >
> > Both in mainline kernel:
> >
> > - Diolan DLN-2 driver: I2C_DLN2 (prompt Diolan DLN-2 USB I2C adapter)
> > Loc: drivers/i2c/busses/
> > - AD7746: AD7746
> > Loc: drivers/staging/iio/cdc/
> >
> > Bus of interest
> > ===============
> >
> > $ sudo i2cdetect -l
> >
> > We get something like:
> >
> > ...
> > i2c-10 i2c dln2-i2c-1-1.2:1.0-0 I2C adapter
> > ...
> >
> > So our bus is the number 10.
> >
> > Getting the address
> > ===================
> >
> > $ sudo i2cdetect -y -r 10
> >
> > We get something like:
> >
> > 0 1 2 3 4 5 6 7 8 9 a b c d e f
> > 00: -- -- -- -- -- -- -- -- -- -- -- -- --
> > 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
> > 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
> > 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
> > 40: -- -- -- -- -- -- -- -- 48 -- -- -- -- -- -- --
> > 50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
> > 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
> > 70: -- -- -- -- -- -- -- --
> >
> > 3. Device instantiation:
> >
> > # echo add7746 0x48 > /sys/bus/i2c/devices/i2c-10/new_device
> >
> > We must see something like:
> >
> > $ cd /sys/bus/i2c/devices/i2c-10/10-0048/
> > $ ls
> > driver iio:device0 modalias name power subsystem uevent
> >
> > $ cd iio:device0
> > $ ls
> > dev in_capacitance-capacitance_calibbias
> > in_capacitance0_calibbias_calibration in_capacitance-capacitance_sampling_frequency
> > in_capacitance0_calibscale in_capacitance-capacitance_scale
> > in_capacitance0_calibscale_calibration in_capacitance_sampling_frequency
> > in_capacitance0-capacitance2_calibscale in_capacitance_sampling_frequency_available
> > in_capacitance0-capacitance2_offset in_capacitance_scale
> > in_capacitance0-capacitance2_raw in_temp0_input
> > in_capacitance0_offset in_temp1_input
> > in_capacitance0_raw in_voltage0_calibscale_calibration
> > in_capacitance1_calibbias_calibration in_voltage0_raw
> > in_capacitance1_calibscale in_voltage1_supply_raw
> > in_capacitance1_calibscale_calibration in_voltage_sampling_frequency
> > in_capacitance1-capacitance3_calibscale in_voltage_sampling_frequency_available
> > in_capacitance1-capacitance3_offset in_voltage_scale
> > in_capacitance1-capacitance3_raw name
> > in_capacitance1_offset power
> > in_capacitance1_raw subsystem
> > in_capacitance_calibbias uevent
> >
> > Checking the permits:
> >
> > $ ll
> > -r--r--r-- 1 root root 4096 mar 31 09:57 dev
> > --w------- 1 root root 4096 mar 31 09:57 in_capacitance0_calibbias_calibration
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_capacitance0_calibscale
> > --w------- 1 root root 4096 mar 31 09:57 in_capacitance0_calibscale_calibration
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_capacitance0-capacitance2_calibscale
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_capacitance0-capacitance2_offset
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_capacitance0-capacitance2_raw
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_capacitance0_offset
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_capacitance0_raw
> > --w------- 1 root root 4096 mar 31 09:57 in_capacitance1_calibbias_calibration
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_capacitance1_calibscale
> > --w------- 1 root root 4096 mar 31 09:57 in_capacitance1_calibscale_calibration
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_capacitance1-capacitance3_calibscale
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_capacitance1-capacitance3_offset
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_capacitance1-capacitance3_raw
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_capacitance1_offset
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_capacitance1_raw
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_capacitance_calibbias
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_capacitance-capacitance_calibbias
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_capacitance-capacitance_sampling_frequency
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_capacitance-capacitance_scale
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_capacitance_sampling_frequency
> > -r--r--r-- 1 root root 4096 mar 31 09:57 in_capacitance_sampling_frequency_available
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_capacitance_scale
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_temp0_input
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_temp1_input
> > --w------- 1 root root 4096 mar 31 09:57 in_voltage0_calibscale_calibration
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_voltage0_raw
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_voltage1_supply_raw
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_voltage_sampling_frequency
> > -r--r--r-- 1 root root 4096 mar 31 09:57 in_voltage_sampling_frequency_available
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 in_voltage_scale
> > -r--r--r-- 1 root root 4096 mar 31 09:57 name
> > drwxr-xr-x 2 root root 0 mar 31 09:57 power
> > lrwxrwxrwx 1 root root 0 mar 31 09:57 subsystem -> ../../../../../../../../../../../bus/iio
> > -rw-r--r-- 1 root root 4096 mar 31 09:57 uevent
> >
> > 4. Capacitance
> >
> > According to [2], the capacitive length sensor is connected to CIN2+ and
> > CIN2-. In the driver, the values are mapped to capacitance0.
> >
> > Raw values vs sensor length:
> >
> > Note: (+) values means the sensor was moved to the left, (-) values
> > means the sensor was moved to the right. I.e. +1 cm means the rule was
> > moved 1 to the left, while -1 means the rule was moved 1 cm to the
> > right.
> >
> > Note2: note the raw value for -10 is 8224733, while +10 is -8224726, the
> > difference is because when the rule is moved 10 cm to the left, the is
> > still 2 o 3 cm of dielectric between the plates. The design is obviously
> > thought to move the rule to the right.
> >
> >
> > Length (cm) | Raw Value Cap0
> > ------------------------------
> > -10 -8224733
> > -9 -8224730
> > -8 -8224728
> > -7 -8224725
> > -6 -8224724
> > -5 -8224722
> > -4 -8224720
> > -3 -8224718
> > -2 -8224716
> > -1 -8224714
> > +0 -8224711
> > +1 -8224711
> > +2 -8224711
> > +3 -8224711
> > +4 -8224713
> > +5 -8224715
> > +6 -8224717
> > +7 -8224719
> > +8 -8224721
> > +9 -8224723
> > +10 -8224726
> >
> >
> > References
> > ==========
> >
> > [1] http://www.analog.com/media/en/technical-documentation/data-sheets/AD7745_7746.pdf
> > [2] http://www.analog.com/media/en/technical-documentation/evaluation-documentation/EVAL-AD7746EB.PDF
> > [3] https://i2c.wiki.kernel.org/index.php/Main_Page
> > [4] https://kernelsense.wordpress.com/2016/01/22/achievement-unlocked-first-iio-driver/
> >
> > _______________________________________________
> > Kernelnewbies mailing list
> > Kernelnewbies at kernelnewbies.org
> > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Hi,
(Sorry for the 'little' late reply)
If still possible, please add me to the editor list so I can edit the page.
My user is 'Gaston Gonzalez'
Thanks !
Gaston
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